1. Field of the Invention
The present invention generally relates to bicycles. More particularly, the present invention relates to a bicycle front fork configured to reduce vibrations transmitted to a rider of the bicycle.
2. Description of the Related Art
Bicycle riding and racing often takes place on less than ideal terrain conditions. For example, bicycle touring and racing may often take place on country roads, which may be unpaved or where the pavement may be rough and irregular, even when new. In more populated areas, a significant portion of paved roads may be damaged and in need of repair. When traversed by the bicycle, these irregular surfaces transmit vibrations to the bicycle. Furthermore, the surface of even relatively new pavement, while acceptable for motor vehicles, may be rough enough to transmit significant vibration to a bicycle. Accordingly, most bicyclists spend at least a significant portion of their riding time traversing rough or irregular surfaces. Vibrations induced by such terrain, if not sufficiently dampened, may be transmitted to the rider of the bicycle. When transmitted to the rider, these vibrations often cause discomfort and fatigue.
Several methods for damping terrain-induced vibrations have been utilized. For example, the bicycle may be equipped with front and/or rear suspension assemblies, which permit the suspended wheel to move against a biasing force relative to the bicycle frame. Although highly favored in some applications, such as bicycles intended primarily for off-road use, such suspension assemblies have generally been unsuccessful in connection with bicycles primarily intended for use on paved surfaces (i.e., road bicycles), where low weight and aerodynamics are considered highly important. Furthermore, such suspension assemblies are intended to absorb large bumps and may not be effective at isolating vibrations due to inherent friction within the assembly, which may prevent movement of the suspension assembly in response to small forces.
In road bicycle applications, it has recently become popular to utilize materials having improved damping properties in comparison to metals to form a portion of the bicycle between the wheels and the rider. For example, a composite material of carbon fiber fabric within a resin matrix (xe2x80x9ccarbon fiberxe2x80x9d) is often used in an attempt to isolate road-induced vibrations from the rider of the bicycle. In some instances, the entire frame of the bicycle may be comprised of a carbon fiber material. However, due to the high manufacturing costs associated with molding carbon fiber, such bicycle frames are expensive to manufacture. Another common method is to produce the main frame of a more conventional material, such as steel, aluminum or titanium, and provide smaller component parts of carbon fiber material in an attempt to reduce vibration. For example, the front fork, seat post, handlebars, and stay portions of the frame (i.e., seat stays and/or chain stays) may be produced from a carbon fiber material.
Such an arrangement has been more successful in isolating terrain-induced vibrations from reaching the rider of the bicycle in comparison with bicycle frames and components comprised entirely of metal. However, although carbon fiber is lightweight and exhibits improved vibration damping characteristics in comparison to metal, a significant amount of vibration may nonetheless be transferred through components made from carbon fiber.
One proposed solution to carbon fibers undesirable transmission of vibrations is to incorporate an additional material into the carbon fiber fabric that is used to make the final carbon fiber product. For example, a weave of titanium filaments has been incorporated into carbon fiber fabric in an attempt to reduce the amount of vibration that is transmitted through components made of carbon fiber. However, such a solution necessitates a complex manufacturing process and, thus, increases the cost of the final product.
Accordingly, a need exists for a cost-effective method of reducing vibrations from being transmitted from the wheels of a bicycle to the rider of the bicycle. Preferred embodiments of the front fork assembly are constructed from a carbon fiber material and includes a cut-out portion on each leg of the fork assembly, which defines a cavity for receiving a separate vibration damping member. Preferably, the vibration damping member is constructed from an elastomeric material and is retained with a friction fit within the cavity of each leg of the front fork.
A preferred embodiment is a bicycle front fork assembly including a steer tube and a pair of fork legs extending in a downward direction from the steer tube and spaced from one another in a lateral direction. Each of the pair of legs has an upper portion, an intermediate portion and a lower portion and defines a substantially fixed length. The fork assembly is configured to support a wheel at the lower portions of the pair of legs and the pair of legs are interconnected at the upper portion. Each of the intermediate portions has an internal wall defining an internal cavity. A damping member is positioned within the cavity and contacts the internal wall. The damping member comprises a vibration damping material.
A preferred embodiment is a bicycle front fork assembly including a steer tube and a pair of hollow, tubular legs extending in a downward direction from the steer tube and spaced from one another in a lateral direction. Each of the pair of legs defines a substantially fixed length. The fork assembly is configured to support a wheel at a lower end of the pair of legs. Each of the pair of legs has an outer wall portion and an internal wall portion. The internal wall portion extends from a first side of the outer wall portion to a second side of the outer wall portion opposite the first side. The internal wall portion defines an internal cavity. A damping member positioned within the cavity and contacts the internal wall. The damping member comprising a vibration damping material.
A preferred embodiment is a bicycle including a frame, which supports a pedal crank assembly and a rear wheel. The pedal crank assembly is configured to drive the rear wheel. A front fork assembly is rotatably supported by the frame for pivotal movement about a steering axis. The fork assembly is configured to support a front wheel of the bicycle at a lower end of the fork. The fork assembly includes a steer tube and a pair of hollow, tubular legs. The pair of legs extend in a downward direction from the steer tube and are spaced from one another in a lateral direction and define a substantially fixed length. Each of the pair of legs has an outer wall portion and an internal wall portion. The internal wall portion extends from a first side of the outer wall portion to a second side of the outer wall portion opposite the first side. The internal wall portion defines an internal cavity. A damping member is positioned within the cavity and contacts the internal wall. The damping member comprises a vibration damping material.
A preferred embodiment is a bicycle including a main frame portion. A front wheel and a rear wheel are connected to the main frame portion. A pedal crank assembly suported by the main frame and being configured to drive the rear wheel. A wheel support portion is connected to the main frame at a first end and supports one of the front wheel and the rear wheel at a second end. The wheel support portion includes a pair of hollow, tubular legs extending along opposing sides of the one of the front wheel and the rear whell. Each of the pair of legs has an outer wall portion and an internal wall portion and defines a sustantially fixed length. The internal wall portion extends from a first side of the outer wall portion to a second side of the outer wall portion opposite the first side. The internal wall portion defines an internal cavity. A damping member is positioned within the cavity and contacts the internal wall. The damping member comprises a vibration damping material.